using System;
using System.Collections.Generic;
using System.Linq;
using static System.Console;

class Program
{
    static void Main()
    {
        var HW = ReadLine().Split();
        var H = int.Parse(HW[0]);
        var W = int.Parse(HW[1]);

        var uf = new UnionFind(H * W);
        var line = ReadLine().Split();
        var zero = W - line.Select(int.Parse).Sum();
        for (int i = 1; i < W; i++)
        {
            var m = W + i;
            if (line[i - 1] == "1" && line[i] == "1") uf.Unite(m - 1, m);
        }
        for (int i = 1; i < H; i++)
        {
            var line2 = ReadLine().Split();
            for (int j = 0; j < W; j++)
            {
                if (line2[j] == "0") zero++;
                else
                {
                    var m = i * W + j;
                    if (j != 0 && line2[j - 1] == "1") uf.Unite(m - 1, m);
                    if (line[j] == "1") uf.Unite(m - W, m);
                }
            }
            line = line2;
        }
        WriteLine(uf.count - zero);
    }
}

class UnionFind
{
    int[] parent;
    public int count;

    public UnionFind(int size)
    {
        var b = new int[size];
        for (int i = 0; i < b.Length; i++)
        {
            b[i] = i;
        }
        parent = b;
        count = size;
    }

    int Root(int x) => parent[x] == x ? x : parent[x] = Root(parent[x]);

    public bool Same(int x, int y) => Root(x) == Root(y);

    public void Unite(int x, int y)
    {
        x = Root(x);
        y = Root(y);
        if (x == y) return;
        count--;
        parent[x] = y;
    }
}